Penetrating Extremity Trauma Endovascular versus Open Repair?

Abstract

Penetrating extremity trauma (PET) accounts for an estimated 5–15% of trauma with vascular injury and these injuries are accountable for a significant percentage of trauma-related deaths. Historically, vascular injuries were best treated by open repair. While a defined selection criteria and a comprehensive algorithm have not been validated, the advancement of endovascular techniques, embolotherapy, and stent grafting have become viable options for the treatment of penetrating arterial extremity trauma in select patients. Advantages endovascular repair offers include decreasing mortality and morbidity associated with open repair, decreasing blood loss, decreasing iatrogenic injury such as nerve injury, and lower rate of wound infection. Patients stability, type of vascular injury, and lesion location are main factors help deciding between endovascular and open repair. Patient selection between endovascular and open repair should be determined by on a case-by-case situation, individual hospital guidelines, a multidisciplinary approach, and technical expertise.

Historical Review of Penetrating Extremity Trauma

Vascular extremity trauma is seen in both military and civilian settings and comes in three forms: blunt, penetrating, and a combination of both. ¹

Within the military setting, the incidence of penetrating extremity trauma (PET) has significantly increased since the beginning of the 20th century. The reported rate of vascular injury during World War I and II was approximately 1%. This number increased to 2 to 3% during the Korean and Vietnam wars before increasing to 12% during the conflicts in Afghanistan and Iraq; this increase is secondary to the use of explosive mechanisms that preferentially affect the lower extremities rather than gunshot mechanism alone. ^{2 3}

The principle surgical strategy during World War I and II was the use of tourniquets and ligation of the bleeding injured artery, which led to an overall amputation rate of 49%. This rate decreased to 13% during the Vietnam War due to the use of arterial reconstruction and rapid transport. ⁴ The amputation rate during the recent Middle East conflicts has ranged from 3 to 20% in part due to the use of early temporary intravascular shunts. ⁵ In an international military cohort study on 597 patients who received lower wartime extremity penetrating trauma, the overall limb salvage rate was 74%. ² The cause of increase in amputation rate compared with Vietnam was attributed to the increased injury due to explosive devices compared with gunshot wounds. Those who were injured with a gunshot mechanism had a 5-year limb salvage rate of 90% with a mortality rate of 1%, drastically improved from the early to mid-1900s. ²

In the civilian setting, upper and lower PET accounts for an estimated 5 to 15% of trauma with vascular injury in roughly 1% of all extremity trauma; however, these injuries are accountable for a significant percentage of trauma-related deaths. ^{6 7} Femoral and popliteal artery injuries are the most common (50–60%), followed by injury to the brachial artery (30%). ¹ The majority of these injuries are caused by handguns (50%), followed by stab wounds (30%) ( Fig. 1 ). ¹ Despite the increase in PET in the civilian setting over the past couple of decades, the overall limb salvage rate has improved to more than 95% due to various advances in treatment, much of which were extrapolated from wartime experience. ⁸

Fig. 1.

Angiogram of a 19-year-old male with self-inflicted gun-shot wound to the left axillary artery. ( a ) Contained arterial extravasation within the left axillary artery with the metallic bullet fragment adjacent to the injured vessel. ( b ) Delayed angiogram shows persistent pooling of contrast confirming injury to the left axillary artery.

Mechanism/Types of Arterial Vascular Injury

Upper and lower extremity vessels can be injured in various ways and by different mechanisms. Partial or complete disruption of the vessel can occur from a projectile or stabbing injury. The vessel can become occluded from joint or bony fragment dislocation or occlusion from compartment syndrome or expanding hematoma. The vessel can also be stressed by extension or compression injuries resulting in dissection or pseudoaneurysm formation. A more delayed type of injury is an arterial-venous fistula. ⁹ The treatment of upper and lower extremity venous injury remains complex and controversial and will not be the focus of this article. ¹⁰

History and Physical Examination

Timely and accurate diagnosis is essential for potential endovascular and surgical interventions in patients with PET to prevent significant morbidity and mortality. Evaluation of patients with PET begins with a history and physical examination. In patients with PET, the physical examination should be focused to triaging patients who may need emergent operation. The Eastern Association for the Surgery of Trauma (EAST) and Western Trauma Association (WTA) have defined the hard and soft signs of vascular injury in patients with PET. ⁹

Hard Signs of Vascular Injury

Traditionally, patients with PET and hard signs of a vascular injury should undergo surgical intervention. Hard signs include distal ischemia, absent distal pulses, active hemorrhage, expanding or pulsatile hematoma, or a new bruit or thrill. ⁹ The classic “six Ps” of distal ischemia include pallor, pain, paresthesia, paralysis, pulselessness, and poikilothermia. Almost 100% of patients with hard signs in an appropriate clinical setting have been found to have a major vascular injury requiring a surgical repair. ¹¹ The hard signs in PET patients have been found to have a sensitivity of 92 to 95% with a positive predictive value of 95% for injuries requiring intervention. ¹² There are certain scenarios where hard signs may not be so helpful; for example, injury to the deep femoral artery may not alter distal pulses, may present without active extravasation, not cause distal ischemia, and it may be difficult to assess for an expanding hematoma or thrill. ⁸ In addition, the anatomic details and localization of the injury may not be possible only with hard signs when there are multiple sites of vascular injury such as a shotgun wound or multiple stab wounds, preexisting vascular disease or repair in the injured extremity, extensive injuries to bone and muscle that may mimic arterial injury, missile track that parallels a vessel, and thoracic outlet injury. In these cases, further preoperative diagnostic technique may be helpful for surgical planning.

Soft Signs

Soft signs may not be helpful in the evaluation of patients with PET, as there is not a high correlation between the soft signs and vascular injury. ^{13 14} Soft signs include small stable hematomas, adjacent nerve injury, unexplained hypotension, and transient history of hemorrhage at the scene. ⁹

Diagnostic Imaging

Arterial Pressure Index

Measurement of the arterial pressure index (API) may be considered in the initial evaluation of selected patients with PET. API measurement is a noninvasive, cost-effective, fast, and relatively reliable screening tool for extremity arterial injury. ¹⁵ APIs are calculated by dividing the distal systolic blood pressure of the injured extremity by the systolic blood pressure in the uninjured paired extremity as measured by Doppler. The API < 0.9 is considered abnormal. The negative predictive value of API > 0.9 has been reported to be up to 96%. ¹⁶ In a prospective study of 1,772 patients with suspected extremity vascular injury, Kurtoğlu et al found that normal API may exclude arterial injury in 99.5% of patients with soft signs and avoids unnecessary secondary examinations in 90% of patients. API measurements therefore should be considered as a diagnostic choice in patient with soft signs. ¹⁷ In a systematic review of 2,161 patients, deSouza et al concluded that normal API in addition to normal physical examination (no hard or soft signs) can rule out an arterial injury. ¹⁸ API, however, has limited diagnostic value in proximal (axillary and groin) injuries, shock, multiple wounds, false aneurysm, intimal flaps, ¹⁹ isolated venous injuries, or arterial disruption in nonaxial collateral beds. ⁹ Arterial spasm in patients with hypovolemic shock may preclude pressure measurement and it may not be possible to place the blood pressure cuff in some patients due to their traumatic injury.

Doppler Sonography

In stable patients with PET, color Doppler sonography may be considered as a screening tool for vascular injury. ⁹ Doppler ultrasound has been described to have a sensitivity of 95% and a specificity of 98% when compared with angiography, exploration, or clinical follow-up. However, Doppler may have a high false-negative rate in patients with shotgun wounds, popliteal, or subclavicular injuries. ²⁰ Doppler sonography is also operator dependent and may require a significant amount of scan time to diagnose a vascular injury; it may especially be limited in the assessment of arterial flow distal to a lesion, and the presence of collateral vasculature may produce erroneous results. ²¹ In a recent study by Montorfano et al, the authors assessed the accuracy of 2-point fast Doppler (2PFD) in triaging 149 limbs of 140 patients with gunshot penetrating injuries. ²² The 2PFD was considered normal when triphasic patterns were present in both the dorsalis pedis artery and posterior tibialis artery, and pathologic when absent, biphasic, or monophasic flow patterns in the dorsalis pedis artery and/or posterior tibialis artery were noted. The 2PFD data were compared with the standard Doppler while matching test reference. In this study, the 2PFD protocol was found to have a sensitivity of 100% and a specificity of 100% compared with the standard Doppler, with 100% true positives rate when matched with the standard Doppler and angiography evaluation results. 2PFD is faster and easier to perform compared with the standard Doppler study, and may be promising as a new first-line screening technique in patient with PET. ²²

Computed Tomographic Angiography

In patients with penetrating extremity injuries computed tomographic angiography (CTA) should be used as the primary initial imaging modality. It has high accuracy in detecting major vascular injury, and is cost-effective, accessible, noninvasive, fast, and easy to interpret ( Fig. 2 ). ^{23 24 25 26} Although physical examination, ankle brachial index (ABI), and ultrasound play a role in the initial examination of the patients, particularly to rule out a significant injury, in patients with high clinical suspicion further evaluation with CTA, catheter angiography, or surgical exploration is warranted. ¹⁸ In a retrospective review of 4,914 trauma patients between 2012 and 2016, 89% of the patient had a CTA as part of their initial evaluation. This study included patients with both blunt and penetrating lower extremity injury. Approximately 82% of patients with injury on CTA also had hard signs of vascular injury on physical examination. These authors concluded that CTA should be reserved for patients with a high clinical suspicion of vascular injury but in the absence of hard signs. ²⁷ In contrast to the study of Protack, Wallin et al evaluated 132 patients with only penetrating lower extremity injuries which were primarily gunshot wounds (89%). In this study, CTA was utilized as an initial evaluation in about half of the patients (45%). All patients with an abnormal CTA had positive findings on operative exploration, and none of the patients with normal CTA needed operative management. ²⁵

Fig. 2.

Polytrauma victim with penetrating trauma to the left upper extremity near the clavicle with persistent bleeding despite surgical intervention. ( a and b ) Axial CTA shows traumatic pseudoaneurysm of the left suprascapular artery with hematoma formation. Images courtesy of Andrew Lipnik, MD; University of Illinois at Chicago.

In the military setting, physical examination may play more significant role in the initial evaluation of patients, while CTA would be useful for confirmation or localization of the source of vascular injuries or to rule out suspected vascular injury. ²⁴ In a retrospective review of 446 patients with penetrating trauma, Colip et al described major vascular trauma in approximately 29% of patients on CTA, 27% of who underwent surgical repair. None of the patient with negative CTA required vascular intervention, leading to the conclusion that CTA is an accurate tool for surgical triage in patients with penetrating trauma. ²³

Finally, CTA has been reported to be 100% specific and sensitive as compared with angiography, with a concurrent cost reduction of $12,922 in patient charges and $1,166 in hospital costs per patient. ^{25 28} CTA is an accurate tool for surgical triage in patients with penetrating trauma and is cost effective.

Angiography

Angiography is the gold standard for diagnosing vascular injuries in patients with PET, although it is invasive and time consuming compared to CTA and is increasingly only performed in selected patients with positive findings on initial non-invasive studies ²⁶ or hard signs. ²⁹ Majority of patients without hard signs on physical examination (95%) have negative angiogram with management decision only changes in less than 2% of patient with no clinical findings. ³⁰ Angiography has a very high sensitivity and specificity for arterial injury, ²⁹ with a very low false-positive rate. ³¹

Angiography also has the benefit of performing simultaneous treatment intervention at the time of diagnosis. Complications have been reported in 1–3% of patients and include local vessel injury, contrast nephropathy, allergic reactions and puncture site complications. ³² Given potential complications, cost, and time needed to perform angiography, it should be only considered in selected patients with suspicious findings on initial physical examination, and non-invasive modalities.

Options for Extremity Arterial Trauma Repair: Endovascular versus Open Repair

Historically, vascular injuries were best treated by open repair. Surgical options include direct vessel repair, venous patch repair, graft placement, and bypass of the injured vessel. However, with the advancement of minimally invasive techniques, a second option utilizing endovascular repair should now also be considered.

Endovascular repair offers an alternative to open surgical repair. If the downstream vessel can be sacrificed, a variety of embolic agents are available to treat extremity trauma patients including Gelfoam (Pfizer, New York, NY), glue, coils, and particles. Gelfoam is the workhorse for trauma patients, as it is readily available, inexpensive, and provides a temporary embolic effect. Typically, Gelfoam's embolic effect lasts approximately 2 weeks before there is recanalization of the embolized vessel. ³³ This gives the vessel time to heal before it is recanalized. Coils and glue can be used in select instances, while particles have more of a role in distal embolization of solid organs and are less likely to be used in extremity arterial trauma. ³⁴

Gelfoam, coil, and glue embolization has been successfully used to treat active bleeding in cases of penetrating arterial extremity trauma ( Fig. 3 ). For example, embolization of the profunda femoris and branch vessels has been documented for the treatment of active hemorrhage and pseudoanueryms. ⁹

Fig. 3.

Same polytrauma victim from Fig. 2 with persistent bleeding in an area of difficult surgical access. ( a ) Digital subtraction angiography with microcatheter parked in the suprascapular artery confirmed traumatic pseudoaneurysm. ( b ) Digital subtraction angiography post endovascular coiling of left suprascapular artery pseudoaneurysm shows successful embolization of the feeding vessel without contrast filling of the pseudoaneurysm. Images courtesy of Andrew Lipnik, MD; University of Illinois at Chicago.

Another endovascular option that can be performed in the treatment of arterial extremity injuries other than the use of embolic agents is the placement of covered stent grafts. Stent grafts are often placed for posttraumatic pseudoaneurysms and arteriovenous fistulae; however, there are an increasing number of studies showing the efficacy of using covered stent grafts in acute traumatic arterial injuries. A multicenter trial involving 62 patients with acute iliac, subclavian, and femoral arterial injuries demonstrated successful endovascular treatment with stent grafts. ³⁵ A review article examining published experiences of endovascular stent graft repair of axillo-subclavian arterial injury concluded that the use of endovascular repair of acute arterial extremity injuries is valid in select patients. ³⁶

Overall, there are published data showing the technical and clinical success rates of endovascular repair of extremity arterial injuries to be 80 to 100% with relatively few complications. ³⁷

Patient Selection for Endovascular versus Open Repair

For patients who have failed conservative management, are hemodynamically unstable, or have convincing signs of arterial vascular injury to the extremity, the next question is often which type of vascular repair is most advantageous—endovascular or open repair?

According to the guidelines issued by the Western Trauma Associated and the Eastern Association for the Surgery of Trauma, endovascular intervention should be applied selectively to hemodynamically stable patients without hard signs of vascular injury, while those who are hemodynamically unstable or have hard signs of vascular injury should go to open repair with trauma/vascular surgery. ³⁸

However, some experts in the field of trauma argue against the need for patient hemodynamic stability as a requirement for endovascular repair. In two small patient series, hemodynamically unstable patients successfully underwent endovascular repair of traumatic subclavian, axillary, and brachial artery injuries. ^{37 39 40}

The peripheral versus central anatomic location of the extremity injury may affect the treatment management. The use of endovascular stent grafts for more central extremity arterial injuries to vessel such as axillary or subclavian arteries has been successful, and is appealing given the technically challenging open surgical approach to repair. ^{37 40} Lower extremity stent grafting has also been successful for common and superficial femoral arterial injuries; however, the majority are used in the setting of dissections, pseudoaneurysm, and arteriovenous fistulae. ³⁸ Future algorithms will likely include anatomic location of the lesion as a major factor in deciding endovascular versus open repair.

Another leading factor in the decision making of endovascular vs open repair will likely be the type of vascular injury. Transected vessels pose the challenge of crossing the lesion through an endovascular approach, which may make them better suited for open repair, whereas dissections, pseudoaneurysms, and arteriovenous fistulas are prime candidates for endovascular repair with any combination of embolization and/or stent grafts.

Finally, an important factor in deciding between endovascular therapy versus open repair is the patency rate of the endovascular stent grafts and the long-term effects of other endovascular embolic therapy. Given the more recent use of sent grafts in penetrating trauma patients, long-term patency studies have not yet been described, and the long-term viability of this type of endovascular therapy should be further assessed. This is especially important in the trauma population, which tends to be made up of younger patients compared to other patient cohorts. ^{36 41 42}

Advantages of endovascular repair includes a decreased mortality and morbidity associated with open repair, decreased blood loss, decreased iatrogenic injury such as nerve injury, and a lower rate of wound infection. ^{41 43} Another consideration is the rising obesity population, which makes open repair more challenging with increased morbidity. With open repair, there is usually a longer postoperative length of stay with a delay in ambulation compared to endovascular therapy. ⁴¹ Endovascular embolization and stent grafting is also typically well tolerated, avoids having to access the traumatized site, and can usually be done with local or moderate sedation. ⁹ Finally, while no definitive cost analysis has been performed, it is likely that open surgical repair is associated with an increased cost compared to endovascular treatment.

Although the advantages of endovascular repair should not be overlooked, not every patient will be a good candidate and there are disadvantages of endovascular treatment compared to open repair. There are technical challenges such as choosing the right embolic agent and size. In many instances, embolization therapy is contraindicated as the downstream vessel cannot be sacrificed. There are challenges of reaching a distal lesion, as well as the challenge of crossing a transected vessel. ^{7 37} Another potential limitation is the absence of an adequate fixation site for a stent graft. ^{36 43} Endovascular therapy has minimal complications; the two most common complications are continued bleeding after treatment, and inadvertent non-targeted distal embolization or non-target embolization. ³⁷ While endovascular techniques have been successfully used in the acute extremity arterial injury setting, a potential limitation is the lack of the immediate availability of an interventional radiology team, as well as the expertise of the team in the setting of trauma. ³⁸ This is likely more feasible in an academic trauma hospital.

While there are no widely available societal recommendations, Baylor University's surgical department formed an algorithm to select patients better suited for endovascular repair instead of open repair based on their medical center's experience. ⁴³ These authors concluded that patients with single proximal extremity injury (not a result of a blast injury) are candidates for endovascular repair. Although this algorithm is based on a single center's experience, it includes in the algorithm that endovascular repair can benefit select patients. There are no clear guidelines or well-defined algorithms to select patients for open surgical repair versus endovascular therapy. There is no consensus on an optimal management algorithm currently and therefore no clear-cut answer to the above question. Patient selection and management therefore should be determined based on a case-by-case situation, individual hospital guidelines, a multidisciplinary approach, and technical expertise.

Case-by-Case, Facility Dependent, Combination Therapy

Currently, the location of single vessel extremity injury in a more central lesion is an indication for endovascular repair, given the complex approach open surgery would require. Patients who have failed conservative medical management or are still bleeding post–surgical repair may be good candidates for endovascular repair. This type of vessel injury is a determining factor, with dissections or pseudoaneurysms as leading factors for embolotherapy or stent grafting.

Combination treatment has also been suggested as a pathway to successful treatment of PET patients. Endovascular therapy can be used as a temporizing/stabilizing technique to bridge the patient to open repair, whether in the acute or elective setting. Balloon occlusion allows for rapid tamponade of active bleeding to stabilize them for open repair. ^{7 42 43}

The surgical literature suggests that having access to a hybrid operating suite should be a factor when approaching treatment options, especially in hemodynamically unstable patients with the thought that endovascular repair can be attempted first in select patients. ⁴³

Summary

In summary, patient selection between endovascular and open repair should be determined by on a case-by-case situation, individual hospital guidelines, a multidisciplinary approach, and technical expertise. While a defined selection criteria and a comprehensive algorithm have not been validated, the advancement of endovascular techniques, embolotherapy and stent grafting have become viable options for the treatment of penetrating arterial extremity trauma in select patients.